<?php

namespace bff\middleware;

use Cache;
use config;
use bff\http\Request;

/**
 * Разрешенные proxy
 * @copyright Tamaranga
 */
class TrustedProxies
{
    public function __invoke(Request $request, $next)
    {
        $request->setTrustedProxies([]); # сбрасываем состояние между запросами

        $trusted = config::get('request.trusted.proxies');
        if (is_null($trusted) || $trusted === '') {
            return $next($request);
        }

        if (is_string($trusted)) {
            if ($trusted === '*') {
                $trusted = [
                    $request->remoteAddress(false, false) # текущий IP
                ];
            } else {
                $trusted = array_map('trim', explode(',', $trusted));
            }
        }
        if (is_array($trusted)) {
            $request->setTrustedProxies(
                $this->mixinCloudFlareIps($trusted)
            );
        }

        return $next($request);
    }

    public function mixinCloudFlareIps(array $trusted, $force = false)
    {
        $key = array_search('cloudflare', $trusted, true);
        if ($key !== false) {
            unset($trusted[$key]);
            $force = true;
        }
        if ($force) {
            $trusted = array_merge($this->loadCloudFlareIps(), $trusted);
        }

        return $trusted;
    }

    public function loadCloudFlareIps($v6 = false)
    {
        $return = [];
        do {
            $cacheKey = 'trusted.proxies.cloudflare';
            if (Cache::has($cacheKey)) {
                $return = Cache::get($cacheKey);
                break;
            }

            $ch = curl_init('https://www.cloudflare.com/ips-v' . ($v6 ? '6' : '4'));
            curl_setopt($ch, CURLOPT_FAILONERROR, 1);
            curl_setopt($ch, CURLOPT_TIMEOUT, 10);
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
            $result = curl_exec($ch);
            if ($result === false) {
                curl_close($ch);
                break;
            }
            $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
            if ($code !== 200) {
                break;
            }
            curl_close($ch);
            $return = array_map('trim', explode(PHP_EOL, $result));
            if (! empty($return)) {
                Cache::add($cacheKey, $return, 172800); // 2 days
            }
        } while (false);

        if (! is_array($return)) {
            return [];
        }
        return $return;
    }
}